Constraining a relativistic mean field model using neutron star mass-radius measurements I: Nucleonic models

TL;DR

This paper uses neutron star mass-radius data to constrain a microscopic nuclear equation of state model, highlighting the potential of future measurements to refine our understanding of dense matter properties.

Contribution

It introduces a field theoretical nuclear EOS model and assesses how current and future measurements can constrain its parameters.

Findings

Current data mainly constrains symmetric nuclear matter EOS.

Future measurements could significantly improve constraints on nuclear symmetry energy.

Microscopic models can be effectively constrained by astrophysical observations.

Abstract

Measurements of neutron star mass and radius or tidal deformability deliver unique insight into the equation of state (EOS) of cold dense matter. EOS inference is very often done using generalized parametric or non-parametric models which deliver no information on composition. In this paper we consider a microscopic nuclear EOS model based on a field theoretical approach. We show that current measurements from NICER and gravitational wave observations constrain primarily the symmetric nuclear matter EOS. We then explore what could be delivered by measurements of mass and radius at the level anticipated for future large-area X-ray timing telescopes. These should be able to place very strong limits on the symmetric nuclear matter EOS, in addition to constraining the nuclear symmetry energy that determines the proton fraction inside the neutron star.